The present invention relates to low-soot and/or non-soot candles that contain paraffin wax.
Paraffin wax is a product of petroleum distillation and is widely used in the production of candles. Paraffin is produced with slightly varying compositions depending on its intended use. Representative paraffin may contain normal paraffins, iso paraffins, cycloalkanes, aromatic compounds including substituted benzenes, substituted toluenes, substituted xylenes, polynuclear aromatics (like phenanthrene, anthracene, etc.), and alkylaromatic compounds of many kinds. Paraffin is used in candles because of its relative abundance, ease of processing, and favorable economics.
In modern candle making, paraffin wax is typically mixed with stearic acid. Varying the percent of paraffin to stearic acid tends to vary candle characteristics such as melting point, crystal structure, opacity, etc. Many of the candles currently sold are paraffin-stearic acid candles with paraffin contents of approximately 85-95% by weight.
A drawback of paraffin candles, however, is that they readily produce soot. Soot, which is largely synonymous with xe2x80x9csmoke,xe2x80x9d is made up of incomplete combustion products. In contrast, complete combustion produces only CO2 and H2O (carbon and hydrogen in their fully oxygenated states). For paraffin containing candles the incomplete combustion products may include polynuclear aromatic materials (such as naphthalene, phenanthrene, anthracene, etc.) and long-chain and/or crossed-linked carbon molecules and polymers thereof. These products may resemble black floating material as they rise from a flame. Soot may be distinguished from usually lighter colored vapor which comprises non-combusted paraffin wax and fragrance chemicals/components. When a candle is extinguished these compounds may be visible as vaporized material that is now condensing. This condensing material is not related to soot.
Soot is not desired because it may contribute to health problems, particularly respiratory ailments and sensitive eye conditions. Soot is also disfavored because it discolors walls, curtains and candle holders, etc., and is otherwise unsightly.
Notwithstanding this disadvantageous aspect of paraffin, paraffin is widely used in the candle industry. Instead of finding a complete alternative to paraffin that is low soot or soot free, it would be highly desirable to be able to produce a candle that contains paraffin (due to its wide acceptance, low-cost and familiarity in the industry), yet does not produce soot or is substantially non-sooting.
As discussed in more detail below, the present invention achieves a non-soot or low-soot paraffin containing candle by combining hydrogenated triglycerides (TGs) and/or free fatty acids (FFAs) with paraffin. The present invention, however, is not the first to combine TGs or FFAs and paraffin (though it is the first to process and combine them in such a manner as to achieve a substantially non-sooting candle). Prior art TG considerations are discussed first, followed by prior art FFA considerations.
U.S. Pat. No. 1,954,659, issued to Will on Aug. 6, 1934, for a Candle and Method of Making Same, teaches a candle that includes xe2x80x9c50% or more vegetable oil combined with paraffin wax, stearic acid, beeswax or other waxes, . . . if the vegetable oil, such as rapeseed oil is first hydrogenated.xe2x80x9d The goal of the Will patent is to process vegetable oil in such a manner as to cause it to change from a liquid to a solid. The type of oil used by Will (e.g., high erucic-content rapeseed) combined with his xe2x80x9chydrogenationxe2x80x9d method achieved a solidification or xe2x80x9chardeningxe2x80x9d of the oil. Nonetheless, Will""s use of the word xe2x80x9chydrogenationxe2x80x9d has a meaning different from hydrogenation as used in the present invention.
Circa 1930, hydrogenation was carried out using a hydrogenation catalyst that favored both (1) hydrogenation of unsaturated triglyceride fatty acid molecules and (2) isomerization of cis (xe2x80x9cZxe2x80x9d) fatty acid isomers to trans (xe2x80x9cExe2x80x9d) fatty acid isomers. Both (1) and (2) result in an increased melting point, and thus the desired xe2x80x9chardeningxe2x80x9d of the oil is achieved without fully hydrogenating the unsaturated triglycerides. This in turn results in a candle that is sufficiently hard for its intended purpose (to be freestanding), but that creates an undesirable amount of soot or smoke due to unsaturated triglycerides.
By circa 1930 standards, it is estimated that the Iodine Value (IV, a measure of the degree of unsaturation of a fatty acid, defined below) for hydrogenated rapeseed oil would have been 15 or greater because of isomerization and high erucic acid content (approximately 20% or higher C22 mono-unsaturated fatty acid content) Thus, a paraffin and TG candle made by Will would have produced significant amounts of soot due to both paraffin and unsaturated TG combustion products.
In contrast to TGs which appear to have not been used in candles for the last 70 years, FFAs have been used (combined with paraffin) regularly from the time of Will to the present. Typically, paraffin/FFA candles are approximately 85-95% paraffin and 5-15% FFA, by weight (amongst other ingredients). The FFA is added to enhance the opacity of the resultant candle. Since hydrogenation techniques have improved since the time of Will, it is now possible to produce stearic acid (a common FFA) that has an IV near 1 and below.
Current paraffin/FFA candles that include this low IV FFA material still produce undesired amounts of soot, however, because the limited amount of low IV FFA in the candle mixture is not sufficient to compensate for the soot (i.e., the combustion products) of the remaining paraffin. This is in part due to the fact that in prior art paraffin/FFA candles, the FFA was not added to reduce soot, but to effect opacity and/or rheology. Thus, a need does exist for a paraffin/FFA candle that is substantially non-sooting.
It should also be recognized that paraffin is derived from a non-renewable source. Therefore, to the extent the present invention uses material other than paraffin in a candle, there is a need to utilize material from a renewable source.
Accordingly, it is an object of the present invention to provide a substantially soot free candle that contains paraffin.
It is another object of the present invention to provide a substantially soot free paraffin containing candle that includes low IV triglycerides.
It is also an object of the present invention to provide a substantially soot free paraffin containing candle that includes low IV free fatty acids.
These and related objects of the present invention are achieved by the substantially non sooting paraffin containing candles as described herein.
The present invention includes at least three groups of candles. Those are paraffin/TG/FFA, paraffin/TG and paraffin/FFA candles. The paraffin/TG/FFA and paraffin/TG candles preferably contain fatty material having an IV of approximately 12.5 or less (thus including IVs of 8, 5, 3, 1, 0.5, etc.).
The paraffin/FFA candles preferably contain greater than approximately 15% FFA by weight (e.g., 20%, 30%, 40%, 50%, 60%, etc.) and the IV of that FFA is preferably approximately 2 or less.
The fatty material (TG or FFA) is preferably plant source, but may be from other sources.
The amount of paraffin in a candle of the present invention may vary widely, depending on TG and/or FFA percentages and IV values, amongst other considerations.
The attainment of the foregoing and related advantages and features of the invention should be more readily apparent to those skilled in the art, after review of the following more detailed description of the invention taken together with the drawings.